rs1202720979

chr6-33441671-C-T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. PP2 BP4 BP6

The NM_006772.3(SYNGAP1):c.2206C>T(p.Arg736Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000547 in 1,461,882 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R736H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: SYNGAP1 NM_006772.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 6.90

Genes affected

SYNGAP1 (HGNC:11497): (synaptic Ras GTPase activating protein 1) This gene encodes a Ras GTPase activating protein that is a member of the N-methyl-D-aspartate receptor complex. The N-terminal domain of the protein contains a Ras-GAP domain, a pleckstrin homology domain, and a C2 domain that may be involved in binding of calcium and phospholipids. The C-terminal domain consists of a ten histidine repeat region, serine and tyrosine phosphorylation sites, and a T/SXV motif required for postsynaptic scaffold protein interaction. The encoded protein negatively regulates Ras, Rap and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor trafficking to the postsynaptic membrane to regulate synaptic plasticity and neuronal homeostasis. Allelic variants of this gene are associated with intellectual disability and autism spectrum disorder. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2016]

SYNGAP1-AS1 (HGNC:53831): (SYNGAP1 antisense RNA 1)

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• PP2: Missense variant where missense usually causes diseases, SYNGAP1
• BP4: Computational evidence support a benign effect (MetaRNN=0.29159236).
• BP6: Variant 6-33441671-C-T is Benign according to our data. Variant chr6-33441671-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 436925.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=2, Likely_benign=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SYNGAP1	NM_006772.3	c.2206C>T	p.Arg736Cys	missense_variant	13/19	ENST00000646630.1
SYNGAP1-AS1	NR_174954.1	n.330-4190G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SYNGAP1	ENST00000646630.1	c.2206C>T	p.Arg736Cys	missense_variant	13/19		NM_006772.3	P1
SYNGAP1-AS1	ENST00000630418.1	n.378-4190G>A		intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251116 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135828

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000547 AC: 8 AN: 1461882 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 727246

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000629

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 31

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Intellectual disability, autosomal dominant 5 Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 02, 2018	This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -
Likely benign, criteria provided, single submitter	clinical testing	Invitae	Jul 26, 2023	- -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Aug 16, 2016

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.083	T
BayesDel_noAF	Benign	-0.36
Cadd	Pathogenic	32
Dann	Pathogenic	1.0
DEOGEN2	Benign	0.14	T;T;.;.;.;.;.;.
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Benign	0.0097	T
MetaRNN	Benign	0.29	T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.2	T
MutationAssessor	Benign	1.6	L;L;.;.;L;L;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.61	T
Polyphen		1.0	D;D;.;.;D;D;.;.
Vest4		0.37, 0.43, 0.36, 0.33
MutPred		0.29		Loss of MoRF binding (P = 0.0015);Loss of MoRF binding (P = 0.0015);Loss of MoRF binding (P = 0.0015);Loss of MoRF binding (P = 0.0015);Loss of MoRF binding (P = 0.0015);Loss of MoRF binding (P = 0.0015);.;.;
MVP		0.17
MPC		2.5
ClinPred		0.93	D
GERP RS		4.7
Varity_R		0.19
gMVP		0.69

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1202720979; hg19: chr6-33409448;